Sweet-smelling stools may indicate an infection with the Clostridioides difficile bacteria, which can occur after recent antibiotic use. Breastfeeding can also cause sweet-smelling stools in babies.

Certain foods and beverages may alter the smell and consistency of stools.

Changes in stool odor can sometimes indicate an underlying health condition or infection. Medications such as antibiotics can also alter the gut microbiome, resulting in stool changes.

Foul-smelling stools, particularly if black and tarry, may be a sign of an underlying health condition.

Persistent stool changes, such as constipation or diarrhea, may indicate a gastrointestinal condition, such as irritable bowel syndrome (IBS).

This article looks at possible causes of sweet-smelling stools, other stool changes to look out for, and when to contact a doctor about stool changes.

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This section looks at possible causes of sweet-smelling stools.

Bacterial infection

An infection with the Clostridioides difficile (C. diff) bacteria may cause sweet-smelling stools, which some people describe as having a “horse barn odor.”

Other symptoms of C. diff include:

A bacterial infection with C. diff usually links to the recent use of antibiotics. Anyone can get a C. diff infection, but risk factors include:

  • being 65 years of age or above
  • recently staying in a nursing home or hospital
  • having a weakened immune system
  • having had a C. diff infection previously or having had exposure to the bacteria

Treatment for a C. diff infection may include discontinuing any antibiotics a person is taking that may be causing the infection and using a different antibiotic, such as vancomycin or fidaxomicin, to treat C. diff.


Certain medications, such as antibiotics, can alter the gut microbiome and change the type and number of bacteria in the colon.

The bacteria in the colon help with digestion, and changes to the bacteria may alter bowel habits. People may find that the consistency, volume, or odor of stools changes.

If people have symptoms of C. diff and have recently used antibiotics, it is best to contact a doctor.

C. diff is contagious, so people will need to take precautions to prevent passing on the infection to others. This includes:

  • washing hands regularly with soap and water before eating and after using the bathroom
  • if people have diarrhea, using a separate bathroom if possible
  • showering and washing with soap

If people have any persistent changes in their bowel habits, such as constipation or diarrhea, they can contact a doctor. People will also need to contact a doctor straight away if they experience:

It is best to speak with a doctor if someone has foul-smelling, black, tarry, or sticky stools.

This section answers some frequently asked questions about sweet-smelling stools.

What does melena smell like?

Melena, or dark, tarry stools, usually has a strong, foul odor. This odor is due to the bacteria and enzyme activity affecting red blood cells in the stools.

Why does my baby’s poop smell sweet?

According to the Australian Breastfeeding Association, while a baby is chest or breastfed, their stool will not have much of a smell. In some cases, the stool may smell sweet.

If a baby starts having formula feeds, the stools may start to smell stronger than they did with chest or breastfeeding alone. The consistency of the stools may also change to become thicker or more well-formed.

Does IBD cause mucus in stool?

Mucus in the stools is a common symptom of ulcerative colitis, a type of inflammatory bowel disease (IBD). Pus or blood may also appear in the stools.

Symptoms of IBD can be different for each person but may include:

  • frequent or urgent need for bowel movements
  • diarrhea
  • cramping
  • abdominal pain
  • fatigue
  • loss of appetite
  • unexplained weight loss

IBS may cause mucus in stools, as well as:

  • bloating
  • abdominal pain
  • cramping
  • gas
  • diarrhea
  • constipation

Certain health conditions, certain foods and drinks, and infections may all alter the smell of stools.

In particular, stools may smell sweet due to a bacterial infection with C. diff. People may also experience diarrhea, stomach pain, or nausea with a C. diff infection. People may develop a C. diff infection after the recent use of antibiotics.

In babies, sweet-smelling stools may occur with chest or breastfeeding. Once a baby is fed formula, the stools may begin to smell stronger.

If people have sweet-smelling stools after antibiotic use, it is best to contact a doctor.

People will also need to contact a doctor if they have any consistent or concerning changes in bowel habits, including blood in the stools, stools that are dark and tarry, or persistent constipation or diarrhea.